Field of the Disclosure
The disclosed subject matter relates generally to camera systems and, more particularly, to employing an automatic white balance technique using histograms generated based on subsampled image data.
Description of the Related Art
The sensors employed in digital cameras have difficulty providing an image where white objects actually appear white to a viewer independent of the light source illuminating the scene. For example, the particular ambient light source (e.g., daylight, tungsten lighting, fluorescent lighting, etc.) affects how the image sensor captures the color information. An automatic white balance (AWB) algorithm attempts to compensate for the difference between the estimated lighting source based on the scene composition and a canonical lighting. Typically, AWB techniques implemented in the camera pipeline employ image statistic approximations to try to match the characteristics of the incoming image to known scenarios to perform the balancing. The efficacy of such techniques depends on detailed knowledge of the particular image sensor being employed and often requires extensive tuning. These limitations increase the cost and length of the development cycle for a camera, such as in a mobile telephone device.
The present disclosure is directed to various methods and devices that may solve or at least reduce some of the problems identified above.
The use of the same reference symbols in different drawings indicates similar or identical items.